There are a number of methods used for treating aquatic weeds such as milfoil. These include mechanical harvesters, manual weed pulling and removal, herbicides and floor screens, barriers or large mats. The use of UV-C light waves is also a potential treatment method as described in the incorporated patent application. The teachings of that application led to this application in order to expand the number and types of treatment methods to battle the growing global environmental problems caused by invasive aquatic species. The infestation of aquatic plants in lakes, ponds and waterways is growing rapidly and prior art methods have not been effective or practical and new and better treatment methods are needed. This invention offers an alternate treatment method that isolates and treats the aquatic plants in a small containment volume of the chamber where herbicides, chemicals or even UV-C light waves can be used to destroy the contained plants. The UV-C ultraviolet light wave treatment method incorporated by reference in this application describes in greater detail may be combined with the apparatus described herein.
Prior art aquatic weed remediation apparatus and methods include mechanical harvesters, mowers, hand pulling, smothering or barrier mats and herbicides are the primary aquatic plant treatment and control methods currently used. One of the above current methods used to treat and kill milfoil (aquatic plants) is barrier mats that cover and smother the plants. Divers swim out to an infected area and submerge a large plastic, or rubber, or fabric mat on top of the milfoil. Some mats are in large rolls that are unrolled underwater. They add weights to hold the mats in place at the floor of the body of water. (The term “floor” used herein refers to the land mass that supports a body of water. The “floor” may also be referred to herein as the bottom or terra firma.) The mat may have slits or vents to allow air and built up gases produced by decaying material to escape. The covered plants are eventually killed by the smothering action of the mats. The mats may remain over the plants for three (3) months before divers retrieve the mats. The retrieved mats need to be cleaned and decontaminated after use. They are usually rolled up for storage until ready for use. Herbicides are also used for treatment and may be applied by surface sprays or by hose directly under water.
The prior art methods an apparatus involve complications. For example, mechanical harvesting methods leave behind large quantities of plant fragments that end up growing and causing additional infestations. Barrier mats require several divers to swim to an infested milfoil plant area and lower the mats over the milfoil. The divers then have to add weights to prevent the mats from drifting away due to water currents. After 3 months, the divers need to return and remove the weights and the mats. Installation and removal is a very time consuming and extremely costly operation. It is also considered dangerous work for the divers. While such mat sit on the floor of the body of water for months, some plants will grow through the vent slits and sediment settles on top of the mats making removal and cleaning of the mats very difficult.
Prior art herbicide use requires large amounts of costly herbicide to obtain the concentrations needed in open bodies of water for treating surface and submerged plants. The herbicide quickly mixes with the water initially forming very high concentrations followed by very low concentration as the herbicide becomes diluted with water. The dilution of the herbicide greatly limits effectiveness. It is virtually impossible to obtain and control the proper concentration for effective treatment. Only a very small fraction of the herbicide ever comes in contact with the plants. Concerns about water pollution and health effects with drinking water contaminated with herbicides along with plants becoming resistant to the applied herbicide and high cost of the herbicide severely limit its use. Allowing large amounts of herbicide to mix and become diluted in open bodies of water facilitates the plants becoming resistant to the herbicide. Once fully diluted the entire body of water is contaminated with herbicide and that can upset the ecosystem. Many unforeseen environmental problems can result.
From the above, it is therefore seen that there exists a need in the art to overcome the deficiencies and limitations described herein and above.